Synthesis gas may be generated by a gasification of carbonaceous feedstocks such as coal, petroleum coke or other carbon-rich feedstocks using oxygen or air and steam at elevated temperature and pressure. In particular, coal gasification with oxygen and steam combined with a shift stage in which the raw synthesis gas form the gasification process is subjected to the water-gas shift reaction offers a route to synthesis gases that may be used for methanol production, the production of liquid hydrocarbons by the Fischer-Tropsch process or the production of synthetic natural gas.